1. Field of the Invention
This invention relates to a rotary driving apparatus having a collet housing which defines a passageway which is adapted to receive, engage and rotate a bur having one end thereof which terminates in a notched bur key formed of a magnetizable material and more specifically to a high speed rotary drill having a collet housing which contains a bearing and which is adapted to have a bur having a notched bur key formed of a magnetizable material at one end thereof slidably inserted into the collet housing wherein the notched bur key is inserted into a capture cavity and removably held in place by a magnet wherein the bur can be easily removed with a slight twist and then withdrawn from the collet housing.
2. Description of the Prior Art
Rotary surgical drills with detachable hand pieces and removable burs are well known in the art. Typical of such known devices are set forth in U.S. Pat. No. 4,055,185; U.S. Pat. No. 3,867,943; U.S. Pat. No. 3,835,858; U.S. Pat. No. 3,709,630; U.S. Pat. No. 3,614,824; U.S. Pat. No. 3,010,193; U.S. Pat. No. 1,905,851; U.S. Pat. No. 3,173,417; U.S. Pat. No. 1,076,971; U.S. Pat. No. 3,128,079; U.S. Pat. No. 3,472,323; and U.S. Pat. No. 3,384,085.
Specifically, U.S. Pat. No. 4,055,185 wherein the inventor is the same inventor of the instant application, the rotary drill adapted for use in surgery has a rotary bur assembly which includes a driven gear and axially aligned spaced bearings. The rotary bur assembly is held within the collet housing by a latching mechanism.
U.S. Pat. No. 3,867,943 discloses a surgical drill with a detachable hand piece wherein the detachable hand piece includes a driven shaft and a claw attached thereto which is adapted to operatively mate with the drive clutch.
U.S. Pat. No. 3,835,858 discloses an improved surgical air drill wherein both the bur and the hand piece are removable and the hand piece is interchangeable with the rotary driving means. A severable coupling between the motor and the hand piece permits interchanging of the hand pieces, which hand pieces include the bur being inserted therein. The bur and its shank is secured to the hand piece shaft in a semi-permanent manner.
It is also known in the art to utilize a magnet or magnetic holding means in a wide variety of apparatus, tools and the like. Typical of such devices are those disclosed in U.S. Pat. No. 4,161,943; U.S. Pat. No. 3,320,563; U.S. Pat. No. 2,718,806; U.S. Pat. No. 2,808,862; U.S. Pat. No. 1,956,634; U.S. Pat. No. 3,257,876; and U.S. Pat. No. 3,253,626.
U.S. Pat. No. 4,161,943 discloses a needle implanting apparatus for implanting magnetized or magnetizable needles and includes a permanent magnet to hold the magnetized needles in a predetermined position for implantation.
U.S. Pat. No. 3,320,563 discloses a magnetic driving implement with cup-shaped magnetic portion for greater holding strength which is adapted to hold bolts in position. The shank of the socket wrench includes a cup-shaped member formed of magnetic material.
U.S. Pat. No. 2,718,806 discloses a magnetic driving tool having a socket which includes a magnet.
U.S. Pat. No. 4,157,714 discloses a portable surgical wire inserting instrument which is adapted to utilize sterile wire pack having a flat end which is adapted to be mounted within the chuck of the wire inserting instrument.